Part 3 - During Incubation
Watching Life Develop
Once incubation is underway, the developing embryo enters a remarkable period of continuous change. Every hour, heat drives countless chemical and biological processes. Nutrients are transferred, organs are formed, bones begin to mineralise, gases are exchanged through the shell, and the growing embryo gradually prepares itself for the challenges of hatching.
Many incubation problems do not begin where they finally become obvious. A chick that dies just before hatching may have been affected by conditions experienced many days earlier. Understanding what is happening inside the egg throughout incubation makes it possible to recognise problems early and to understand why they occur.
This section follows the developing embryo through the incubation period, explaining how temperature, humidity, gas exchange, egg turning and metabolic heat interact to influence the final outcome.
Topics in this section
Heat-Driven Development
Embryo development is driven by heat. Learn why temperature controls the rate of development, why excessive heat is far more damaging than slightly low temperatures, and why many late hatch problems actually begin during the earliest stages of incubation.
➡ Read: Heat-Driven Development
Formation and Development
The embryo does not simply grow larger—it passes through distinct stages. This chapter explains why the first part of incubation is devoted primarily to forming the body's structures, while the later stages concentrate on growth and maturation.
➡ Read: Formation and Development
Humidity During Incubation
Humidity influences much more than the size of the air-cell. Learn how water loss, gas exchange and embryo development are linked, and why successful humidity management is measured over the entire incubation period rather than from one day to the next.
➡ Read: Humidity During Incubation
Egg Weight Loss
The developing embryo must lose the correct amount of water throughout incubation. Discover how a simple weight-loss graph provides one of the most accurate ways of monitoring humidity and predicting hatch success.
➡ Read: Egg Weight Loss
Egg Turning
Turning continues to play an essential role throughout incubation. Learn how regular turning assists normal embryo positioning, reduces malpositions and supports healthy development.
➡ Read: Egg Turning
Metabolic Heat
As the embryo grows, it begins producing significant amounts of heat itself. Learn why older eggs may become warmer than younger eggs, and why understanding metabolic heat is important when incubating mixed-age batches.
➡ Read: Metabolic Heat
Power Failures
Power interruptions are always worrying, but they are not always disastrous. Learn how embryos respond to falling temperatures, what actions are helpful, and which common reactions often do more harm than good.
➡ Read: Power Failures
Recommended reading for first-time incubators
If you are following the Guide for the first time, we recommend reading these chapters in the following order:
- Heat-Driven Development
- Formation and Development
- Humidity During Incubation
- Egg Weight Loss
- Egg Turning
- Metabolic Heat
- Power Failures
By the end of this section you will understand not only how the embryo develops, but also why small changes in incubation conditions can have consequences many days later.
Ready to continue?
As incubation draws to a close, the embryo begins preparing for its greatest challenge—the transition from life inside the egg to life in the outside world. The next section explains the remarkable sequence of events that lead to hatching, and why patience is often one of the incubator's most important settings.
Continue to → Part 4 – Hatching
The Greatlander Incubation Guide
Understanding development before understanding hatch problems.
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